The Ukrainian Jewish community has appealed for help in the wake of the turmoil following the overturn of the government and invasion by Russia.

Rabbi Misha Kapustin, head of the Reform movement in Crimea, said the situation in Simferopol was becoming more threatening by the day.

In an email sent across the diaspora on Sunday, he wrote: “Our town, Simferopol, is occupied by the Russians. Help us, save our country, save Ukraine! Ask your government for help!”

Speaking from his synagogue on Wednesday, the rabbi, who was ordained at Leo Baeck College in London, said: “On the same day that the Russians entered Crimea, our synagogue was vandalised with fascist graffiti. They wrote ‘death to kikes’ and drew swastikas.

“For the first time in my life, I asked my congregation to go home on a Friday and not return for the Saturday service — at least until we’ve significantly improved our security measures.

“There were troops with machine guns only 100 metres away from the synagogue.”

Leading Ukrainian rabbis have accused President Vladimir Putin of provoking anti-Jewish incidents in Crimea in order to justify Russia’s invasion.

In a press conference on Tuesday, Mr Putin said: “We see the rampage of reactionary forces, nationalist and antisemitic forces, going on in certain parts of Ukraine, including Kiev.”

World Jewish Relief, the agency that helps more than 16,000 vulnerable Ukrainian Jews, warned of the “extremely fragile situation” creating an economic “vacuum” that would affect pensions and worsen already “chronic” poverty.

The charity has set up a crisis fund to provide extra support for its programmes in Kiev, Zaporozhye, Lvov, Kharkov, Krivoy Rog and across the country.

Paul Anticoni, WJR chief executive, promised that the London-based charity “would not let down” those relying on its services.

“The majority of our clients are dependent on the state for their pension and on us to supplement it. They will immediately suffer. Those people have no savings, no assets, they have not got much capital to liquidate to cover the months-long absence of a pension,” he said. “The interim government is looking at what’s in the treasury and realising there’s not much there. The pledges we had from Moscow are now in question. The US and Europe are not yet making the pledges to allow such financing to continue.”

The far-right party Svoboda, which played a role in ousting former president Viktor Yanukovich, has enjoyed an upswing of support.

Despite many in Crimea appearing happy with the Russian involvement, Rabbi Kapustin published an open letter calling for a continuation of Ukrainian sovereignty in the area.

Kiev-based Rabbi Dukhovny said: “Our new government is accused of being antisemitic, but we only had four cases of antisemitism during three months of revolution — and we think they have been provoked by Russia so that President Putin can say he is fighting antisemitism.” On Tuesday, a group of Jewish intellectuals, lay leaders and rabbis signed a letter to Mr Putin, asking him to withdraw troops and stop referring to Ukrainian antisemitism.

“We don’t need him to save us,” said Rabbi Dukhovny. “We want Ukraine to be based on justice, equality and pluralism, and that is what we have been working towards without him.”

Rabbi Dukhovny said prominent Jews including Vladimir Groisman and Igor Kolomoisky had been given ministerial roles in the new pro-European government. He said that Jews largely felt safe, apart from those in Crimea.

“In Kiev, we are fine. It has settled down since the revolution, and we are carrying on with full services in our synagogues as normal,” said Rabbi Dukhovny.

A group of rabbis met US Secretary of State John Kerry when he visited the capital on Tuesday.

Antisemitism has been an issue since the beginning of the crisis, with Russian allies accusing the opposition of being “rampantly antisemitic”. Anti-Russian parties have tried to counter that. Dmitry Yarosh, the leader of the far-right Pravy Sektor met Israel’s envoy to the Ukraine in an attempt to change his party’s image.